Hybrid maize plant and seed (3375)

ABSTRACT

According to the invention, there is provided a hybrid maize plant, designated as 3375, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. This invention relates to the hybrid seed 3375, the hybrid plant produced from the seed, and variants, mutants, and trivial modifications of hybrid 3375.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relating to a hybrid maize line designated 3375.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant. A plant is cross-pollinated if the pollen comes from a flower on a different plant.

Plants that have been self-pollinated and selected for type for many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two different homozygous lines produces a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants each heterozygous at a number of gene loci will produce a population of hybrid plants that differ genetically and will not be uniform.

Maize (Zea mays L.), often referred to as corn in the United States, can be bred by both self-pollination and cross-pollination techniques. Maize has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in maize when wind blows pollen from the tassels to the silks that protrude from the tops of the ears.

The development of a hybrid maize variety involves three steps: (1) the selection of plants from various germplasm pools for initial breeding crosses; (2) the selfing of the selected plants from the breeding crosses for several generations to produce a series of inbred lines, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred lines with unrelated inbred lines to produce the hybrid progeny (F₁). During the inbreeding process in maize, the vigor of the lines decreases. Vigor is restored when two different inbred lines are crossed to produce the hybrid progeny (F₁). An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid created by crossing a defined pair of inbreds will always be the same. Once the inbreds that create a superior hybrid have been identified, a continual supply of the hybrid seed can be produced using these inbred parents and the hybrid corn plants can then be generated from this hybrid seed supply.

Large scale commercial maize hybrid production, as it is practiced today, requires the use of some form of male sterility system which controls or inactivates male fertility. A reliable method of controlling male fertility in plants also offers the opportunity for improved plant breeding. This is especially true for development of maize hybrids, which relies upon some sort of male sterility system. There are several options for controlling male fertility available to breeders, such as: manual or mechanical emasculation (or detasseling), cytoplasmic male sterility, genetic male sterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility system incorporating manual or mechanical detasseling. Alternate strips of two inbred varieties of maize are planted in a field, and the pollen-bearing tassels are removed from one of the inbreds (female). Providing that there is sufficient isolation from sources of foreign maize pollen, the ears of the detasseled inbred will be fertilized only from the other inbred (male), and the resulting seed is therefore hybrid and will form hybrid plants.

The laborious, and occasionally unreliable, detasseling process can be avoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile as a result of factors resulting from the cytoplasmic, as opposed to the nuclear, genome. Thus, this characteristic is inherited exclusively through the female parent in maize plants, since only the female provides cytoplasm to the fertilized seed. CMS plants are fertilized with pollen from another inbred that is not male-sterile. Pollen from the second inbred may or may not contribute genes that make the hybrid plants malefertile. Usually seed from detasseled fertile maize and CMS produced seed of the same hybrid are blended to insure that adequate pollen loads are available for fertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterility available, such as multiple mutant genes at separate locations within the genome that confer male sterility, as disclosed in U.S. Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations as described by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. These and all patents referred to are incorporated by reference. In addition to these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patent application Ser. No. 07/848,433, have developed a system of nuclear male sterility which includes: identifying a gene which is critical to male fertility; silencing this native gene which is critical to male fertility; removing the native promoter from the essential male fertility gene and replacing it with an inducible promoter; inserting this genetically engineered gene back into the plant; and thus creating a plant that is male sterile because the inducible promoter is not "on" resulting in the male fertility gene not being transcribed. Fertility is restored by inducing, or turning "on" the promoter, which in turn allows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in the art, each with its own benefits and drawbacks. These methods use a variety of approaches such as delivering into the plant a gene encoding a cytotoxic substance associated with a male tissue specific promoter or an antisense system in which a gene critical to fertility is identified and an antisense to that gene is inserted in the plant (see: Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCT application PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use of gametocides. Gametocides are not a genetic system, but rather a topical application of chemicals. These chemicals affect cells that are critical to male fertility. The application of these chemicals affects fertility in the plants only for the growing season in which the gametocide is applied (see Carlson, Glenn R., U.S. Pat. No.: 4,936,904). Application of the gametocide, timing of the application and genotype specificity often limit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production of maize hybrids. The development of maize hybrids requires, in general, the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Breeding programs combine the genetic backgrounds from two or more inbred lines or various other broad-based sources into breeding pools from which new inbred lines are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which of those have commercial potential.

There are many important factors to be considered in the art of plant breeding, such as the ability to recognize important morphological and physiological characteristics, the ability to design evaluation techniques for genotypic and phenotypic traits of interest, and the ability to search out and exploit the genes for the desired traits in new or improved combinations.

The objective of commercial maize hybrid line development programs is to develop new inbred lines to produce hybrids that combine to produce high grain yields and superior agronomic performance. The primary trait breeders seek is yield. However, many other major agronomic traits are of importance in hybrid combination and have an impact on yield or other,wise provide superior performance in hybrid combinations. Such traits include percent grain moisture at harvest, relative maturity, resistance to stalk breakage, resistance to root lodging, grain quality, and disease and insect resistance. In addition, the lines per se must have acceptable performance for parental traits such as seed yields, kernel sizes, pollen production, all of which affect ability to provide parental lines in sufficient quantity and quality for hybridization. These traits have been shown to be under genetic control and many if not all of the traits are affected by multiple genes.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodology for new hybrid line development.

In general terms this procedure consists of crossing two inbred lines to produce the non-segregating F₁ generation, and self pollination of the F₁ generation to produce the F₂ generation that segregates for all factors for which the inbred parents differ. An example of this process is set forth below. Variations of this generalized pedigree method are used, but all these variations produce a segregating generation which contains a range of variation for the traits of interest.

EXAMPLE 1 Hypothetical Example of Pedigree Breeding Program

Consider a cross between two inbred lines that differ for alleles at five loci. The parental genotypes are: ##EQU1## the F₁ from a cross between these two parents is: ##EQU2## Selfing F₁ will produce an F₂ generation including the following genotypes: ##EQU3##

The number of genotypes in the F₂ is 3⁶ for six segregating loci (729) and will produce (2⁶)-2 possible new inbreds, (62 for six segregating loci).

Each inbred parent which is used in breeding crosses represents a unique combination of genes, and the combined effects of the genes define the performance of the inbred and its performance in hybrid combination. There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen, R. A. Tenborg and S. J. Wall, TAG. 80:833-840 (1990)) that each of the lines are different and can be uniquely identified on the basis of genetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Fo. Quantitative Genetics in Maize Breeding, Iowa State University Press, Ames Iowa, 1981) that most traits of economic value in maize are under the genetic control of multiple genetic loci, and that there are a large number of unique combinations of these genes present in elite maize germplasm. If not, genetic progress using elite inbred lines would no longer be possible. Studies by Duvick and Russell (Duvick, D. N., Maydica 37:69-79, (1992); Russell, W. A., Maydica XXIX:375-390 (1983)) have shown that over the last 50 years the rate of genetic progress in commercial hybrids has been between one and two percent per year.

The number of genes affecting the trait of primary economic importance in maize, grain yield, has been estimated to be in the range of 10-1000. Inbred lines which are used as parents for breeding crosses differ in the number and combination of these genes. These factors make the plant breeder's task more difficult. Compounding this is evidence that no one line contains the favorable allele at all loci, and that different alleles have different economic values depending on the genetic background and field environment in which the hybrid is grown. Fifty years of breeding experience suggests that there are many genes affecting grain yield and each of these has a relatively small effect on this trait. The effects are small compared to breeders' ability to measure grain yield differences in evaluation trials. Therefore, the parents of the breeding cross must differ at several of these loci so that the genetic differences in the progeny will be large enough that breeders can develop a line that increases the economic worth of its hybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines is n, the number of unique genotypes in the F₂ generation is 3" and the number of unique inbred lines from this cross is {(2")-2}. Only a very limited number of these combinations are useful. Only about 1 in 10,000 of the progeny from F₂ 's are commercially useful.

By way of example, if it is assumed that the number of segregating loci in F₂ is somewhere between 20 and 50, and that each parent is fixed for half the favorable alleles, it is then possible to calculate the approximate probabilities of finding an inbred that has the favorable allele at {(n/2)+m} loci, where n/2 is the number of favorable alleles in each of the parents and m is the number of additional favorable alleles in the new inbred. See Example 2 below. The number m is assumed to be greater than three because each allele has so small an effect that evaluation techniques are not sensitive enough to detect differences due to three or less favorable alleles. The probabilities in Example 2 are on the order of 10⁻⁵ or smaller and they are the probabilities that at least one genotype with (n/2)=m favorable alleles will exist.

To put this in perspective, the number of plants grown on 60 million acres (approximate United States corn acreage) at 25,000 plants/acre is 1.5×10¹².

EXAMPLE 2 Probability of Finding an Inbred With m of n Favorable Alleles

Assume each parent has n/2 of the favorable alleles and only 1/2 of the combinations of loci are economically useful.

    ______________________________________                                                 No. of                                                                         favorable                                                              No. of  alleles in                                                                               No. additional                                               segregating                                                                            Parents   favorable alleles in                                                                         Probability that                               loci (n)                                                                               (n/2)     new inbred    genotype occurs*                               ______________________________________                                         20      10        14            3 × 10.sup.-5                            24      12        16            2 × 10.sup.-5                            28      14        18            1 × 10.sup.-5                            32      16        20            8 × 10.sup.-6                            36      18        22            5 × 10.sup.-6                            40      20        24            3 × 10.sup.-6                            44      22        26            2 × 10.sup.-6                            48      24        28            1 × 10.sup.-6                            ______________________________________                                          *Probability that a useful combination exists, does not include the            probability of identifying this combination if it does exist.            

The possibility of having a usably high probability of being able to identify this genotype based on replicated field testing would be most likely smaller than this, and is a function of how large a population of genotypes is tested and how testing resources are allocated in the testing program.

Pioneer research station staff propose about 400 to 500 new inbreds each year from over 2,000,000 pollinations. Of those proposed new inbreds, less than 50, and more commonly less than 30, are actually selected for commercial use.

SUMMARY OF THE INVENTION

According to the invention, there is provided a hybrid maize plant, designated as 3375, produced by crossing two Pioneer Hi-Bred International, Inc proprietary inbred maize lines. This invention thus relates to the hybrid seed 3375, the hybrid plant produced from the seed, and variants, mutants, and trivial modifications of hybrid 3375. This hybrid maize plant is characterized by high yield, superior Brittle Stalk resistance, and good Head Smut resistance. It is best adapted for the North Central Region of the Corn Belt.

DEFINITIONS

In the description and examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. NOTE: ABS is in absolute terms and %MN is percent of the mean for the experiments in which the inbred or hybrid was grown. These designators will follow the descriptors to denote how the values are to be interpreted. Below are the descriptors used in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9 visual rating indicating the resistance to Anthracnose Stalk Rot. A higher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap in paired comparisons and on a 1 to 9 scale (9=highest resistance) in Characteristics Charts.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushels per acre adjusted to 15.5% moisture.

CLN=CORN LETHAL NECROSIS (synergistic interaction of maize chlorotic mottle virus (MCMV) in combination with either maize dwarf mosaic virus (MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV)). A 1 to 9 visual rating indicating the resistance to Corn Lethal Necrosis. A higher score indicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicating the resistance to Common Rust. A higher score indicates a higher resistance.

CRM=COMPARATIVE RELATIVE MATURITY (see PRM).

D/D=DRYDOWN. This represents the relative rate at which a hybrid will reach acceptable harvest moisture compared to other hybrids on a 1-9 rating scale. A high score indicates a hybrid that dries relatively fast while a low score indicates a hybrid that dries slowly.

DIE=DROPPED EARS. Represented in a 1 to 9 scale in the Characteristics Chart, where 9 is the rating representing the least, or no, dropped ears.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodia macrospora). A 1 to 9 visual rating indicating the resistance to Diplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for drought tolerance, and is based on data obtained under stress conditions. A high score indicates good drought tolerance and a low score indicates poor drought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in inches. This is represented in a I to 9 scale in the Characteristics Chart, where 9 is highest.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a 1" is very susceptible and a 9" is very resistant. This is based on overall rating for ear mold of mature ears without determining the specific mold organism, and may not be predictive for a specific ear mold. 5

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostdnia nubilalis). A 1 to 9 visual rating indicating the resistance to preflowering leaf feeding by first generation European Corn Borer. A higher score indicates a higher resistance.

ECB 2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING (Ostrinia nubilalis). Average inches of tunneling per plant in the stalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1 to 9 visual rating indicating post flowering degree of stalk breakage and other evidence of feeding by European Corn Borer, Second Generation. A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Dropped ears due to European Corn Borer. Percentage of plants that did not drop ears under second generation corn borer infestation.

E/G=EARLY GROWTH. This represents a 1 to 9 rating for early growth, scored when two leaf collars are visible.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on per plot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visual rating indicating the resistance to Eye Spot. A higher score indicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusarium subglutinans). A 1 to 9 visual rating indicating the resistance to Fusarium ear rot. A higher score indicates a higher resistance.

G/A=GRAIN APPEARANCE. Appearance of grain in the grain tank (scored down for mold, cracks, read streak, etc.).

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, that assumes that maize growth occurs in the temperature range 50° F.-86° F. and that temperatures outside this range slow down growth; the maximum daily heat unit accumulation is 36 and the minimum daily heat unit accumulation is 0. The seasonal accumulation of GDU is a major factor in determining maturity zones.

GDU PHY=GDU TO PHYSIOLOGICAL MATURITY. The number of growing degree units required for an inbred or hybrid line to have approximately 50 percent of plants at physiological maturity from time of planting. Growing degree units are calculated by the Barger method.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: ##EQU4##

The highest maximum temperature used is 86° F. and the lowest minimum temperature used is 50° F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visual rating indicating the resistance to Gibberella Ear Rot. A higher score indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual rating indicating the resistance to Gray Leaf Spot. A higher score indicates a higher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual rating indicating the resistance to Goss' Wilt. A higher score indicates a higher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plant densities on 1-9 relative rating system with a higher number indicating the hybrid responds well to high plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum). A 1 to 9 visual rating indicating the resistance to Helminthosporium infection. A higher score indicates a higher resistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates the percentage of plants not infected.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acre assuming drying costs of two cents per point above 15.5 percent harvest moisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybrid on per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1 over variety #2.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plant densities on a 1-9 relative system with a higher number indicating the hybrid responds well to low plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus and MCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating the resistance to Maize Dwarf Mosaic Complex. A higher score indicates a higher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 over variety #2 as calculated by: MOISTURE of variety #2-MOISTURE of variety #1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilum turcicum). A 1 to 9 visual rating indicating the resistance to Northern Leaf Blight. A higher score indicates a higher resistance.

PHY CRM=CRM at physiological maturity.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in inches. This is represented as a 1 to 9 scale, 9 highest, in the Characteristics Chart.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

It should be understood that the inbred can, through routine manipulation of cytoplasmic or other factors, be produced in a male-sterile form. Such embodiments are also contemplated within the scope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage of variety #1 over variety #2 as calculated by PLANT POPULATION of variety #2-PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety #1.

PRM=PREDICTED Relative Maturity. This trait, predicted relative maturity, is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is referred to as the Comparative Relative Maturity Rating System that is similar to the Minnesota Relative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required to reach 50% pollen shed. Relative values are predicted values from the linear regression of observed GDU's on relative maturity of commercial checks.

PRO=PROTEIN RATING. Rating on a 1 to 9 scale comparing relative amount of protein in the grain compared to hybrids of similar maturity. A "1" score difference represents a 0.4 point change in grain protein percent (e.g., 8.0% to 8.4%).

P/Y=PROTEIN/YIELD RATING. Indicates, on a I to 9 scale, the economic value of a hybrid for swine and poultry feeders. This takes into account the income due to yield, moisture and protein content.

ROOTS (%)=Percent of stalks NOT root lodged at harvest.

R/L=ROOT LODGING. A 1 to 9 rating indicating the level of root lodging resistance. The higher score represents higher levels of resistance.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis as an approximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1 over variety #2.

S/L=STALK LODGING. A 1 to 9 rating indicating the level of stalk lodging resistance. The higher scores represent higher levels of resistance.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A maize breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolaris maydis). A 1 to 9 visual rating indicating the resistance to Southern Leaf Blight. A higher score indicates a higher resistance.

SLK CRM=CRM at Silking.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual rating indicating the resistance to Southern Rust. A higher score indicates a higher resistance.

STA GRN=STAYGREEN. Staygreen is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STAND (%)=Percent of stalks standing at harvest.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 over variety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STK LDG=STALK LODGING. This is the percentage of plants that did not stalk lodge (stalk breakage) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear.

STW WLT=Stewart's Wilt (Erwinia stewartiii). A 1 to 9 visual rating indicating the resistance to Stewart's Wilt. A higher score indicates a higher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at the time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data is given as a percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT (CHARACTERISTICS CHART)=Test weight on a 1 to 9 rating scale with a 9 being the highest rating.

TST VVT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1 over variety #2.

WIN M%=PERCENT MOISTURE WINS.

WIN Y%=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety #2 as calculated by: YIELD of variety #1-YIELD variety #2=yield advantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Pioneer Brand Hybrid 3375 is a single cross, yellow endosperm, dent maize hybrid. Hybrid 3375 demonstrates an unexpected combination of high yield with superior Brittle Stalk resistance. Hybrid 3375 has stable yield across environments and has good Head Smut resistance. In addition 3375 has good silage characteristics.

This hybrid has the following characteristics based on the data collected primarily at Johnston, Iowa.

                  TABLE 1                                                          ______________________________________                                         VARIETY DESCRIPTION INFORMATION                                                HYBRID = PIONEER BRAND 3375                                                    ______________________________________                                         Type: Dent     Region Best Adapted: West                                       A.  Minnesota Relative Maturity Rating (harvest moisture): 118                     GDU's to Physiological Maturity (black layer): 2670                            GDU's to 50% Silk: 1380                                                    B.  Plant Characteristics:                                                         Plant height (to tassel tip): 316 cm                                           Length of top ear internode: 19 cm                                             Number of ears per stalk: Single                                               Ear height (to base of top ear): 123 cm                                        Number of tillers: None                                                        Cytoplasm type: Normal                                                     C.  Leaf:                                                                          Color: (WF9) Medium Green*                                                     Angle from Stalk: <30 degrees                                                  Marginal Waves: (WF9) Few                                                      Number of Leaves (mature plants): 20                                           Sheath Pubescence: (W22) Light                                                 Longitudinal Creases: (OH56A) Few                                              Length (Ear node leaf): 101 cm                                                 Width (widest point, ear node leaf): 11 cm                                 D.  Tassel:                                                                        Number lateral branches: 9                                                     Branch Angle from central spike: 30-40 degrees                                 Pollen Shed: (KY21) Heavy                                                      Peduncle Length (top leaf to basal branches): 28 cm                            Anther Color: Red*                                                             Glume Color: Green*                                                        E.  Ear (Husked Ear Data Except When Stated Otherwise):                            Length: 20 cm                                                                  Weight: 232 gm                                                                 Mid-point Diameter: 50 mm                                                      Silk Color: Pink*                                                              Husk Extension (Harvest stage): Medium (Barely                                 covering ear)                                                                  Husk Leaf: Long (>15 cm)                                                       Taper of Ear: Slight                                                           Position of Shank (dry husks): Upright                                         Kernel Rows: Straight, Distinct Number = 18                                    Husk Color (fresh): Light Green*                                               Husk Color (dry): Buff*                                                        Shank Length: 12 cm                                                            Shank (No. of internodes): 9                                               F.  Kernel (Dried):                                                                Size (from ear mid-point)                                                      Length: 13 mm                                                                  Width: 8 mm                                                                    Thick: 4 mm                                                                    Shape Grade (% rounds): 16                                                     Pericarp Color: Colorless*                                                     Aleurone Color Homozygous Yellow*                                              Endosperm Color: Yellow*                                                       Endosperm Type: Normal Starch                                                  Gm Wt/100 Seeds (unsized): 34 gm                                           G.  Cob:                                                                           Diameter at mid-point: 26 mm                                                   Strength: Strong                                                               Color: Red*                                                                H.  Diseases:                                                                      Corn Lethal Necrosis (MCMV = Maize Chlorotic                                   Mottle Virus and MDMV = Maize                                                  Dwarf Mosaic Virus): Intermediate                                              Maize Dwarf Mosaic Complex (MDMV & MCDV =                                      Maize Dwarf Virus): Susceptible                                                Anthracnose Stalk Rot (C. graminicola): Intermediate                           S. Leaf Blight (B. maydis): Resistant                                          N. Leaf Blight (E. turcicum): Susceptible                                      Eye Spot (K. zeae): Resistant                                                  Gray Leaf Spot (C. zeae): Susceptible                                          Goss's Wilt (C. nebraskense): Resistant                                        Fusarium Ear Mold (F. moniliforme): Intermediate                               Gibberelia Ear Rot (G. zeae): Resistant                                    I.  Insects:                                                                       European Corn Borer-2 (Post-flowering): Resistant                              The above descriptions are based on a scale of 1-9,                            1 being highly susceptible, 9 being highly resistant.                          S (Susceptible): Would generally represent a score of 1-3.                     I (Intermediate): Would generally represent a score of 4-5.                    R (Resistant): Would generally represent a score of 6-7.                       H (Highly Resistant): Would generally represent a                              score of 8-9. Highly resistant does not imply the                              inbred is immune.                                                          J.  Variety Most Closely Resembling:                                           Character    Hybrid                                                            Maturity     Pioneer Brand 3394                                                Usage        Pioneer Brand 3394                                                ______________________________________                                          *In interpreting the foregoing color designations, reference may be had t      the Munsell Glossy Book of Color, a standard color reference.                  Data for Items B, C, D, E, F, and G is based primarily on a maximum of tw      reps from Johnston, Iowa grown in 1994.                                  

Research Comparisons for Pioneer Hybrid 3375

Comparisons of characteristics for Pioneer Brand Hybrid 3375 were made against Pioneer Brand Hybrids 3394, 3398, 3379, 3373, 3348 and 3417. Table 2A compares Pioneer Brand Hybrid 3375 and Pioneer Brand Hybrid 3394. The results show Hybrid 3375 is significantly higher yielding than Hybrid 3394. Hybrid 3375 has taller plants with significantly higher Brittle Stalk resistance than Hybrid 3394.

Table 2B compares Pioneer Hybrid 3375 and Pioneer Hybrid 3398. The results show Hybrid 3375 is significantly higher yielding than Hybrid 3398. Hybrid 3375 plants are taller with higher ear placement than Hybrid 3398 plants. In addition, Hybrid 3375 has significantly higher Brittle Stalk resistance than Hybrid 3398.

Table 2C compares Pioneer Hybrid 3375 and Pioneer Hybrid 3379. The results show Hybrid 3375 is significantly higher yielding than Hybrid 3379. Hybrid 3375 plants are taller with higher ear placement than Hybrid 3379 plants. In addition, Hybrid 3375 has higher Brittle Stalk resistance than Hybrid 3379.

Table 2D compares Pioneer Hybrid 3375 and Pioneer Hybrid 3373. The results show Hybrid 3375 is higher yielding than Hybrid 3373. Hybrid 3375 has significantly taller plants with higher ear placement than Hybrid 3373.

Table 2E compares Pioneer Hybrid 3375 and Pioneer Hybrid 3348. The results show Hybrid 3375 is higher yielding than Hybrid 3348. Pioneer Hybrid 3375 has taller plants with higher ear placement than Hybrid 3348. Hybrid 3375 has significantly higher Brittle Stalk resistance than Hybrid 3348.

Table 2F compares Pioneer Hybrid 3375 and Pioneer Hybrid 3417. The results show Hybrid 3375 is significantly higher yielding than Hybrid 3417. Pioneer Hybrid 3375 has significantly taller plants with higher ear placement than Pioneer Hybrid 3417. In addition, Hybrid 3375 demonstrates significantly higher Brittle Stalk resistance than Hybrid 3417.

                                      TABLE 2A                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3394                                                              __________________________________________________________________________                 BU   BU        TST  SDG  EST  TIL GDU                                      VAR ACR  ACR  MST  WT   VGR  CNT  LER SHD                                      #   ABS  %MN  ABS  ABS  ABS  ABS  ABS ABS                              __________________________________________________________________________     TOTAL SUM                                                                              1   181.1                                                                               106  21.9 56.4 5.8  53.6 14.1                                                                               135.0                                    2   172.0                                                                               100  20.5 56.8 6.7  55.0 2.6 137.5                                    LOCS                                                                               462  462  472  253  169  217  4   121                                      REPS                                                                               587  587  600  326  232  284  4   152                                      DIFF                                                                               9.1  5    1.4  0.4  1.0  1.4  11.6                                                                               2.5                                      PROB                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .216                                                                               .000#                            __________________________________________________________________________                 GDU     POL                                                                               PLT    EAR RT    STA STK                                        VAR SLK     SC HT     HT  LDG   GRN LDG                                        #   ABS     ABS                                                                               ABS    ABS ABS   ABS ABS                                __________________________________________________________________________     TOTAL SUM                                                                              1   136.0   8.0                                                                               112.5  48.4                                                                               91.9  5.4 94.3                                       2   137.1   7.0                                                                               108.8  48.6                                                                               93.5  5.5 95.3                                       LOCS                                                                               63      1  196    196 121   167 316                                        REPS                                                                               77      1  251    251 158   217 417                                        DIFF                                                                               1.1     1.0                                                                               3.7    0.2 1.6   0.1 0.9                                        PROB                                                                               .000#      .000#  .557                                                                               .270  .430                                                                               .036+                              __________________________________________________________________________                 BRT     GRN DRP    GLF NLF    SLF                                                                               GOS                                       VAR STK     APP EAR    SPT BLT    BLT                                                                               WLT                                       #   ABS     ABS ABS    ABS ABS    ABS                                                                               ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   95.5    7.3 98.8   2.9 2.6    6.7                                                                               7.5                                       2   87.6    7.0 98.8   2.6 4.8    5.0                                                                               7.5                                       LOCS                                                                               169     81  112    22  8      3  1                                         REPS                                                                               190     98  149    32  14     6  2                                         DIFF                                                                               7.9     0.3 0.0    0.3 2.1    1.7                                                                               0.0                                       PROB                                                                               .000#   .074*                                                                              .863   .179                                                                               .000#  .109                                 __________________________________________________________________________                 ANT     HD        MDM FUS    GIB                                                                               EYE                                        VAR ROT     SMT CLN   CPX ERS    ERS                                                                               SPT                                        #   ABS     ABS ABS   ABS ABS    ABS                                                                               ABS                                __________________________________________________________________________     TOTAL SUM                                                                              1   4.1     99.1                                                                               4.7   3.3 4.8    7.3                                                                               5.4                                        2   4.1     99.5                                                                               5.8   3.3 2.8    7.7                                                                               3.3                                        LOCS                                                                               7       5   3     1   2      1  8                                          REPS                                                                               13      10  6     3   3      3  11                                         DIFF                                                                               0.0     0.5 1.2   0.0 2.0    0.3                                                                               2.1                                        PROB                                                                               .000#   .712                                                                               .118      .000#     .000#                              __________________________________________________________________________                 COM     SOU                                                                               HC     ECB ECB   ECB ECB                                        VAR RST     RST                                                                               BLT    DPE 1LF   2SC 2IT                                        #   ABS     ABS                                                                               ABS    ABS ABS   ABS ABS                                __________________________________________________________________________     TOTAL SUM                                                                              1   6.0     2.5                                                                               7.5    98.8                                                                               3.9   5.5 2.0                                        2   6.0     3.5                                                                               6.0    99.3                                                                               3.8   5.4 0.7                                        LOCS                                                                               2       1  1      16  3     31  1                                          REPS                                                                               2       2  2      18  6     43  3                                          DIFF                                                                               0.0     1.0                                                                               1.5    0.4 0.1   0.1 1.3                                        PROB                                                                               .000#             .384                                                                               .926  .734                                   __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2B                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3398                                                              __________________________________________________________________________                 BU   BU       TST SDG EST GDU  GDU  PLT                                    VAR ACR  ACR  MST WT  VGR CNT SHD  SLK  HT                                     #   ABS  % MN ABS ABS ABS ABS ABS  ABS  ABS                            __________________________________________________________________________     TOTAL SUM                                                                              1   174.2                                                                               109  23.0                                                                               55.6                                                                               5.1 63.2                                                                               133.4                                                                               135.8                                                                               110.3                                  2   151.4                                                                               94   22.8                                                                               55.8                                                                               4.7 63.0                                                                               130.9                                                                               133.6                                                                               99.2                                   LOCS                                                                               40   40   41  29  20  25  10   4    23                                     REPS                                                                               57   57   58  38  30  39  17   6    30                                     DIFF                                                                               22.8 15   0.2 0.3 0.4 0.1 2.5  2.1  11.1                                   PROB                                                                               .000#                                                                               .000#                                                                               .517                                                                               .273                                                                               .232                                                                               .911                                                                               .001#                                                                               .026+                                                                               .000#                          __________________________________________________________________________                 EAR   RT  STA    STK BRT    GRN DRP   ECB                                  VAR HT    LDG GRN    LDG STK    APP EAR   1LF                                  #   ABS   ABS ABS    ABS ABS    ABS ABS   ABS                          __________________________________________________________________________     TOTAL SUM                                                                              1   48.3  97.3                                                                               5.4    96.8                                                                               94.9   7.5 99.4  6.0                                  2   40.5  99.5                                                                               3.4    96.3                                                                               85.4   7.0 99.9  7.0                                  LOCS                                                                               23    20  16     35  24     6   20    1                                    REPS                                                                               30    30  22     50  33     6   31    1                                    DIFF                                                                               7.8   2.2 2.0    0.4 9.5    0.5 0.6   1.0                                  PROB                                                                               .000# .247                                                                               .001#  .749                                                                               .005#  .415                                                                               .076*                              __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2C                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3379                                                              __________________________________________________________________________                 BU   BU       TST  SDG EST  TIL                                                                               GDU                                         VAR ACR  ACR  MST WT   VGR CNT  LER                                                                               SHD                                         #   ABS  % MN ABS ABS  ABS ABS  ABS                                                                               ABS                                 __________________________________________________________________________     TOTAL SUM                                                                              1   166.0                                                                               109  23.9                                                                               55.2 5.0 56.6 37.2                                                                              134.2                                       2   147.2                                                                               96   23.6                                                                               54.6 5.1 59.3 10.9                                                                              136.7                                       LOCS                                                                               60   60   62  50   33  43   1  19                                          REPS                                                                               77   77   79  59   43  57   1  26                                          DIFF                                                                               18.9 14   0.3 0.6  0.2 2.7  26.3                                                                              2.6                                         PROB                                                                               .000#                                                                               .000#                                                                               .222                                                                               .021+                                                                               .610                                                                               .001#   .001#                               __________________________________________________________________________                 GDU  PLT   EAR  RT    STA STK   BRT                                        VAR SLK  HT    HT   LDG   GRN LDG   STK                                        #   ABS  ABS   ABS  ABS   ABS ABS   ABS                                __________________________________________________________________________     TOTAL SUM                                                                              1   137.2                                                                               112.4 47.0 96.6  5.4 95.6  96.2                                       2   139.3                                                                               107.8 45.4 96.5  4.7 96.6  91.2                                       LOCS                                                                               9    33    33   27    22  55    29                                         REPS                                                                               11   42    42   38    27  70    39                                         DIFF                                                                               2.1  4.7   1.6  0.2   0.7 0.9   5.0                                        PROB                                                                               .055*                                                                               .000# .027+                                                                               .924  .075*                                                                              .294  .065*                              __________________________________________________________________________                 GRN   DRP  NLF   ECB  ECB  ECB ECB                                         VAR APP   ERS  BLT   DPE  1LF  2SC 2IT                                         #   ABS   ABS  ABS   ABS  ABS  ABS ABS                                 __________________________________________________________________________     TOTAL SUM                                                                              1   7.1   99.2 3.0   98.2 3.9  5.1 2.0                                         2   6.5   100.0                                                                               3.0   100.0                                                                               4.0  5.9 1.7                                         LOCS                                                                               24    29   1     5    3    11  1                                           REPS                                                                               24    40   1     7    6    13  3                                           DIFF                                                                               0.6   0.7  0.0   1.8  0.1  0.8 0.3                                         PROB                                                                               .100  .007#      .085*                                                                               .885 .074*                                   __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2D                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3373                                                              __________________________________________________________________________                 BU   BU       TST  SDG  EST  TIL GDU                                       VAR ACR  ACR  MST WT   VGR  CNT  LER SHD                                       #   ABS  % MN ABS ABS  ABS  ABS  ABS ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   173.4                                                                               104  22.3                                                                               56.4 5.4  51.5 11.4                                                                               135.3                                     2   169.0                                                                               103  22.1                                                                               55.6 5.0  51.1 0.7 131.5                                     LOCS                                                                               207  207  215 155  88   128  4   67                                        REPS                                                                               311  311  326 210  127  200  4   83                                        DIFF                                                                               4.4  2    0.1 0.8  0.5  0.4  10.7                                                                               3.8                                       PROB                                                                               .004#                                                                               .079*                                                                               .259                                                                               .000#                                                                               .012+                                                                               .399 .276                                                                               .000#                             __________________________________________________________________________                 GDU  PLT  EAR  RT   STA  STK  BRT GRN                                      VAR SLK  HT   HT   LDG  GRN  LDG  STK APP                                      #   ABS  ABS  ABS  ABS  ABS  ABS  ABS ABS                              __________________________________________________________________________     TOTAL SUM                                                                              1   136.6                                                                               111.9                                                                               49.0 93.0 5.0  93.3 95.7                                                                               7.1                                      2   132.3                                                                               105.4                                                                               45.1 87.9 3.4  90.8 94.5                                                                               6.9                                      LOCS                                                                               50   93   93   81   87   157  66  52                                       REPS                                                                               57   122  122  118  118  229  83  55                                       DIFF                                                                               4.3  6.5  3.9  5.1  1.7  2.5  1.2 0.2                                      PROB                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .037+                                                                               .000#                                                                               .006#                                                                               .331                                                                               .299                             __________________________________________________________________________                 DRP  GLF    NLF                                                                               SLF  ANT                                                                               HD       MDM                                        VAR EAR  SPT    BLT                                                                               BLT  ROT                                                                               SMT   CLN                                                                               CPX                                        #   ABS  ABS    ABS                                                                               ABS  ABS                                                                               ABS   ABS                                                                               ABS                                __________________________________________________________________________     TOTAL SUM                                                                              1   99.4 3.1    2.6                                                                               7.0  4.1                                                                               100.0 4.0                                                                               3.3                                        2   99.8 2.2    3.8                                                                               6.5  3.5                                                                               100.0 3.0                                                                               2.3                                        LOCS                                                                               62   12     4  1    4  2     1  1                                          REPS                                                                               84   17     7  2    7  4     2  3                                          DIFF                                                                               0.4  0.9    1.1                                                                               0.5  0.6                                                                               0.0   1.0                                                                               1.0                                        PROB                                                                               .039+                                                                               .002#  .186    .623                                                                              1.00                                        __________________________________________________________________________                 FUS                                                                               GIB  EYE COM   ECB  ECB   ECB ECB                                       VAR ERS                                                                               ERS  SPT RST   DPE  1LF   2SC 2IT                                       #   ABS                                                                               ABS  ABS ABS   ABS  ABS   ABS ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   5.0                                                                               7.3  5.2 6.0   98.9 3.9   5.7 2.0                                       2   4.0                                                                               7.0  3.8 7.0   100.0                                                                               6.3   5.5 1.7                                       LOCS                                                                               2  1    6   2     14   3     18  1                                         REPS                                                                               4  3    7   2     16   6     21  3                                         DIFF                                                                               1.0                                                                               0.3  1.4 1.0   1.1  2.4   0.3 0.3                                       PROB                                                                               .295    .013+                                                                              .500  .093*                                                                               .034+ .630                                  __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2E                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3348                                                              __________________________________________________________________________                 BU   BU       TST  SDG EST  TIL GDU  GDU                                   VAR ACR  ACR  MST WT   VGR CNT  LER SHD  SLK                                   #   ABS  % MN ABS ABS  ABS ABS  ABS ABS  ABS                           __________________________________________________________________________     TOTAL SUM                                                                              1   173.5                                                                               104  22.6                                                                               56.1 5.6 50.7 11.4                                                                               135.1                                                                               136.3                                 2   169.8                                                                               102  22.7                                                                               55.0 5.8 52.5 3.1 133.2                                                                               133.7                                 LOCS                                                                               222  222  229 158  102 133  4   66   48                                    REPS                                                                               334  334  348 212  146 208  4   82   54                                    DIFF                                                                               3.6  2    0.1 1.1  0.2 1.8  8.3 1.9  2.6                                   PROB                                                                               .004#                                                                               .003#                                                                               .266                                                                               .000#                                                                               .193                                                                               .000#                                                                               .320                                                                               .000#                                                                               .000#                         __________________________________________________________________________                 PLT  EAR  RT  STA STK  BRT  GRN  DRP GLF                                   VAR HT   HT   LDG GRN LDG  STK  APP  EAR SPT                                   #   ABS  ABS  ABS ABS ABS  ASS  ABS  ABS ABS                           __________________________________________________________________________     TOTAL SUM                                                                              1   113.8                                                                               50.4 92.2                                                                               5.3 92.7 96.1 7.2  99.4                                                                               2.9                                   2   110.8                                                                               46.7 92.3                                                                               5.0 94.0 88.0 6.3  99.5                                                                               4.6                                   LOCS                                                                               104  104  82  101 172  39   59   64  22                                    REPS                                                                               140  140  122 141 255  54   67   90  32                                    DIFF                                                                               3.0  3.7  0.1 0.3 1.3  8.1  0.9  0.1 1.7                                   PROB                                                                               .000#                                                                               .000#                                                                               .952                                                                               .122                                                                               081* .001#                                                                               .000#                                                                               .718                                                                               .000#                         __________________________________________________________________________                  NLF  SLF   GOS ANT    HD       MDM FUS                                    VAR  BLT  BLT   WLT ROT    SMT CLN  CPX ERS                                    #    ABS  ABS   ABS ABS    ABS ABS  ABS ABS                            __________________________________________________________________________     TOTAL SUM                                                                              1    2.6  6.7   7.5 4.1    99.1                                                                               4.8  3.3 5.3                                    2    5.3  5.0   8.0 5.0    98.3                                                                               4.0  2.7 4.5                                    LOCS 8    3     1   7      5   2    1   2                                      REPS 14   6     2   13     10  4    3   3                                      DIFF 2.6  1.7   0.5 0.9    0.8 0.8  0.7 0.8                                    PROB .000#                                                                               .109      .070*  .679                                                                               .656     .656                           __________________________________________________________________________                   GIB                                                                               EYE   COM SOU   ECB ECB    ECB ECB                                    VAR   ERS                                                                               SPT   RST RST   DPE 1LF    2SC 2IT                                    #     ABS                                                                               ABS   ABS ABS   ABS ABS    ABS ABS                            __________________________________________________________________________     TOTAL SUM                                                                              1     7.3                                                                               5.2   6.0 2.5   98.8                                                                               4.0    5.9 2.7                                    2     4.7                                                                               5.3   5.5 4.0   96.8                                                                               5.7    5.9 2.6                                    LOCS  1  6     2   1     14  4      19  2                                      REPS  3  7     2   2     18  9      24  6                                      DIFF  2.7                                                                               0.1   0.5 1.5   2.0 1.8    0.0 0.0                                    PROB     .872  .795      .197                                                                               .039+  .986                                                                               .942                           __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2F                                     __________________________________________________________________________     PAIRED COMPARISON REPORT                                                       VARIETY #1 = 3375                                                              VARIETY #2 = 3417                                                              __________________________________________________________________________                 BU   BU        TST  SDG EST  TIL GDU                                       VAR ACR  ACR  MST  WT   VGR CNT  LER SHD                                       #   ABS  % MN ABS  ABS  ABS ABS  ABS ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   172.8                                                                               107  23.0 56.0 5.6 55.6 13.1                                                                               135.2                                     2   158.1                                                                               98   21.7 55.8 5.3 56.4 2.5 131.9                                     LOCS                                                                               201  201  206  154  98  134  4   67                                        REPS                                                                               279  279  284  206  127 174  4   85                                        DIFF                                                                               14.8 10   1.3  0.2  0.3 0.9  10.5                                                                               3.3                                       PROB                                                                               .000#                                                                               .000#                                                                               .000#                                                                               .019+                                                                               .117                                                                               .080*                                                                               .303                                                                               .000#                             __________________________________________________________________________                 GDU  POL PLT  EAR  RT   STA  STK BRT                                       VAR SLK  SC  HT   HT   LDG  GRN  LDG STK                                       #   ABS  ABS ABS  ABS  ABS  ABS  ABS ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   136.7                                                                               8.0 111.7                                                                               47.3 91.3 5.6  94.2                                                                               95.7                                      2   134.5                                                                               7.0 103.6                                                                               38.3 98.3 4.6  93.3                                                                               88.2                                      LOCS                                                                               39   1   106  106  64   94   166 90                                        REPS                                                                               49   1   135  135  87   125  228 106                                       DIFF                                                                               2.3  1.0 8.1  8.9  7.0  1.1  0.9 7.5                                       PROB                                                                               .000#    .000#                                                                               .000#                                                                               .001#                                                                               .000#                                                                               .237                                                                               .000#                             __________________________________________________________________________                 GRN  DRP    GLF NLF  SLF                                                                               GOS   ANT                                                                               HD                                        VAR APP  EAR    SPT BLT  BLT                                                                               WLT   ROT                                                                               SMT                                       #   ABS  ABS    ABS ABS  ABS                                                                               ABS   ABS                                                                               ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1   7.2  99.2   3.1 2.9  7.0                                                                               7.5   4.2                                                                               98.4                                      2   6.5  99.8   2.9 3.0  7.5                                                                               7.5   3.2                                                                               98.4                                      LOCS                                                                               56   66     9   4    1  1     3  3                                         REPS                                                                               68   93     13  7    2  2     6  6                                         DIFF                                                                               0.7  0.6    0.1 0.1  0.5                                                                               0.0   1.0                                                                               0.0                                       PROB                                                                               .002#                                                                               .005#  .816                                                                               .836          .438                                                                              1.00                              __________________________________________________________________________                  CLN                                                                               EYE   COM HC    ECB ECB  ECB ECB                                       VAR  ERS                                                                               SPT   RST BLT   DPE 1LF  2SC 2IT                                       #    ABS                                                                               ABS   ABS ABS   ABS ABS  ABS ABS                               __________________________________________________________________________     TOTAL SUM                                                                              1    5.0                                                                               5.6   6.0 7.5   98.7                                                                               5.0  5.5 3.3                                       2    3.8                                                                               4.3   3.5 6.5   99.3                                                                               5.2  5.1 2.6                                       LOCS 2  7     2   1     15  2    32  1                                         REPS 4  9     2   2     17  4    45  3                                         DIFF 1.3                                                                               1.3   2.5 1.0   0.6 0.2  0.4 0.7                                       PROB .500                                                                              .002# .344      .379                                                                               .874 .251                                  __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

Strip Test Data for Hybrid 3375

Comparison data was collected from strip tests that were grown by farmers. Each hybrid was grown in strips of 4, 6, 8, 12, etc. rows in fields depending on the size of the planter used. The data was collected from strip tests that had the hybrids in the same area and weighed. The moisture percentage was determined and bushels per acre was adjusted to 15.5 percent moisture. The number of comparisons represent the number of locations or replications for the two hybrids that were grown in the same field in close proximity and compared.

Comparison strip testing was done between Pioneer Brand Hybrid 3375 and Pioneer Brand Hybrids 3394, 3398, 3379, 3373, 3348 and 3417. The comparisons come from all the hybrid's adapted growing areas in the United States.

These results are presented in Table 3. Hybrid 3375 has a yield advantage over all of the hybrids. Hybrid 3375 shows a weighted average income advantage of $1.65 per acre. Hybrid 3375's yield and income advantage plus its advantage for other characteristics over these hybrids will make it an important addition for most areas where these hybrids are grown.

                                      TABLE 3                                      __________________________________________________________________________     PIONEER HYBRID 3375 VS. PIONEER HYBRIDS 3394, 3398, 3379, 3373, 3348 and       3417                                                                           FROM 1994 STRIP TESTS                                                          __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   186.8                                                                               19.9 384.19                                                                               25.4  93   96   57.3                            PIONEER 3394   183.7                                                                               18.4 383.17                                                                               25.2  95   97   57.6                            Advantage      3.1  -1.5 1.02  0.2   -2   -1   -0.6                            # Comparisons  664  664  664   359   230  193  563                             Percent Wins   58   10   50    43    23   6    16                              Prob. of Dim.  99   99   66    83    99   96   99                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   170.2                                                                               19.7 350.83                                                                               20.9  91   93   56.9                            PIONEER 3398   160.0                                                                               18.0 335.63                                                                               20.7  94   85   57.5                            Advantage      10.2 -1.7 15.20 0.2   -3   8    -0.6                            # Comparisons  16   16   16    10    6    6    16                              Percent Wins   75   6    62    50    33   16   12                              Prob. of Dim.  99   99   97    27    47   44   98                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   195.3                                                                               18.5 407.10                                                                               25.9  87   97   58.4                            PIONEER 3379   187.3                                                                               18.6 390.02                                                                               26.2  87   95   57.9                            Advantage      8.0  0.1  17.08 -0.3  0    2    0.5                             # Comparisons  36   36   36    15    7    5    33                              Percent Wins   66   47   72    33    42   20   54                              Prob. of Dim.  99   34   99    47    28   43   98                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   188.6                                                                               20.3 386.54                                                                               25.0  92   95   57.2                            PIONEER 3373   187.6                                                                               20.0 385.90                                                                               24.7  88   92   56.5                            Advantage      1.0  -0.3 0.64  0.3   4    3    0.7                             # Comparisons  435  435  435   253   175  159  364                             Percent Wins   54   33   53    45    43   23   61                              Prob. of Dim.  83   99   37    97    99   99   99                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   186.0                                                                               20.6 380.22                                                                               25.0  93   96   57.0                            PIONEER 3348   183.0                                                                               20.5 374.76                                                                               24.4  94   96   55.8                            Advantage      3.0  -0.1 5.46  0.6   -1   0    1.2                             # Comparisons  285  285  285   176   124  112  235                             Percent Wins   61   32   57    51    27   10   81                              Prob. of Dim.  99   93   99    99    64   4    99                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   192.4                                                                               19.8 396.00                                                                               25.3  91   96   57.4                            PIONEER 3417   190.4                                                                               18.4 396.56                                                                               25.7  91   99   57.2                            Advantage      2.0  -1.4 -0.56 -0.4  0    -3   0.2                             # Comparisons  454  454  454   231   157  136  386                             Percent Wins   56   12   47    32    37   4    43                              Prob. of Dim.  99   99   28    97    2    99   99                              __________________________________________________________________________                              INCOME                                                                               POP   STAND                                                                               ROOTS                                                                               TEST                            BRAND   PRODUCT                                                                               YIELD                                                                               MOIST                                                                               /ACRE K/ACRE                                                                               (%)  (%)  WT                              __________________________________________________________________________     PIONEER 3375   188.5                                                                               20.1 387.12                                                                               25.2  92   96   57.3                            Weighted Avg   186.0                                                                               19.1 385.47                                                                               25.0  92   96   57.1                            Advantage      2.5  -1.0 1.65  0.2   0    0    0.2                             # Comparisons  1890 1890 1890  1044  699  611  1597                            Percent Wins   57   20   51    43    32   1 1  43                              Prob. of Dim.  99   99   99    98    55   20   99                              __________________________________________________________________________

Comparison of Key Characteristics for Hybrid 3375

Characteristics of Pioneer Hybrid 3375 are compared to Pioneer Hybrids 3394, 3398, 3379, 3373, 3348 and 3417 in Table 4. The values given for most of the traits are on a 1-9 basis. In these cases 9 would be outstanding, while 1 would be poor for the given characteristics. These values are based on performance of a given hybrid relative to other Pioneer commercial, precommercial and competitive hybrids that are grown in research and strip test trials. These performance based values are determined utilizing several factors such as research data, experience the trained corn researchers had in the field, and sales experience with the hybrids in strip tests and the field. These values reflect the hybrid's relative performance to other hybrids for the characteristics listed. Table 4 shows Hybrid 3375 yielded very well and maintains yield stability in both high and low population densities. In addition, Hybrid 3375 has better Brittle Stalk resistance compared to the other hybrids. Hybrid 3375 has overall high yield, excellent Brittle Stalk resistance and other agronomic characteristics which should make it an important hybrid in its area of adaptation.

                                      TABLE 4                                      __________________________________________________________________________     Hybrid Patent Comparisons-Characteristics                                      Pioneer Hybrid 3375 vs. Pioneer Hybrids 3394, 3398, 3379, 3373, 3348 and       3417                                                                           __________________________________________________________________________               SILK                                                                               PHY GDU GDU    H/ L/                                             VARIETY                                                                              CRM CRM CRM SILK                                                                               PHY YLD                                                                               POP                                                                               POP                                                                               D/D                                                                               SIL                                                                               R/L                                   __________________________________________________________________________     3375  111 111 110 1380                                                                               2670                                                                               9  9  9  7  7  5                                     3394  110 111 111 1380                                                                               2700                                                                               9  9  9  8  7  7                                     3398  111 109 110 1360                                                                               2670                                                                               6  6  7  5  5  6                                     3379  111 113 112 1410                                                                               2720                                                                               7  7  5  8  7  5                                     3373  111 107 109 1330                                                                               2640                                                                               9  8  9  5  4  4                                     3348  111 108 111 1350                                                                               2700                                                                               9  9  8  6  7  5                                     3417  109 108 110 1350                                                                               2670                                                                               8  8  9  8  5  6                                     __________________________________________________________________________           STA     TST         PLT                                                                               ER    BRT                                         VARIETY                                                                              GRN D/T WT  G/A E/G HT HT D/E                                                                               STK                                                                               PRO                                                                               P/Y                                   __________________________________________________________________________     3375  7       6   5   5   6  6  5  7  6  9                                     3394  8   8   6   5   8   5  5  5  4  5  9                                     3398  3   9   5   7   3   4  3  6  2  5  6                                     3379  8   8   5   5   4   5  5  6  5  5  7                                     3373  4       4   5   4   4  4  5  6  5  9                                     3348  6       4   4   6   6  4  4  3  6  9                                     3417  5   7   5   5   5   4  2  6  2  4  7                                     __________________________________________________________________________

INDUSTRIAL APPLICABILITY

This invention includes hybrid maize seed of 3375 and the hybrid maize plant produced therefrom. The foregoing was set forth by way of example and is not intended to limit the scope of the invention.

As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which maize plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants, or parts of plants, such as embryos, pollen, ovules, flowers, kernels, ears, cobs, leaves, seeds, husks, stalks, roots, root tips, anthers, silk and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflects that 97% of the plants cultured which produced callus were capable of plant regeneration. Subsequent experiments with both inbreds and hybrids produced 91% regenerable callus which produced plants. In a further study in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988), 7:262-265 reports several media additions which enhance regenerability of callus of two inbred lines. Other published reports also indicated that nontraditional" tissues are capable of producing somatic embryogenesis and plant regeneration. K. P. Rao, et al., Maize Genetics Cooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesis from glume callus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347 (1987) indicates somatic embryogenesis from the tissue cultures of maize leaf segments. Thus, it is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, "conventional" in the sense that they are routinely used and have a very high rate of success.

Tissue culture of maize is described in European Patent Application, publication 160,390, incorporated herein by reference. Maize tissue culture procedures are also described in Green and Rhodes, Plant Regeneration in Tissue Culture of Maize, Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982, at 367-372) and in Duncan, et al., The Production of Callus Capable of Plant Regeneration from Immature Embryos of Numerous Zea Mays Geneotypes, 165 Planta 322-332 (1985). Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce maize plants having the genotype of 3375.

Maize is used as human food, livestock feed, and as raw material in industry. The food uses of maize, in addition to human consumption of maize kernels, include both products of dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch in the wet-milling industry and maize flour in the dry-milling industry. The industrial applications of maize starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The maize starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of maize are also used in industry. Stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of the hybrid maize plant and various parts of the hybrid maize plant can be utilized for human food, livestock feed, and as a raw material in industry.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims. Applicants have made a deposit of at least 2500 seeds of Hybrid Corn Line 3375 with the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA, ATCC Deposit No. 97514. The seeds deposited with the ATCC on Apr. 22, 1996 were taken from the same deposit maintained by Pioneer Hi-Bred International, Inc., 700 Capital Square, 400 Locust Street, Des Moines, Iowa 50309-2340 since prior to the filing date of this application. This deposit of the Hybrid Corn Line 3375 will be maintained in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the enforceable life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Additionally, Applicant has satisfied all the requirements of 37 C.F.R. §§1.801-1.809, including providing an indication of the viability of the sample. Applicant imposes no restrictions on the availability of the deposited material from the ATCC; however, Applicant has no authority to waive any restrictions imposed by law on the transfer of biological material or its transportation in commerce. Applicant does not waive any infringement of its rights granted under this patent. 

What is claimed is:
 1. Hybrid maize seed designated 3375, representative seed having been deposited and having ATCC accession number
 97514. 2. A maize plant and its parts produced by the seed of claim
 1. 3. Pollen of the plant of claim
 2. 4. An ovule of the plant of claim
 2. 5. A tissue culture of regenerable cells of a hybrid maize plant 3375, grown from the seed of claim 1, wherein the tissue generates plants capable of expressing all the morphological and physiological characteristics of
 3375. 6. A tissue culture according to claim 5, the tissue culture selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silks, flowers, kernels, ears, cobs, husks, stalks, and cells, and protoplasts thereof.
 7. A maize plant regenerated from the tissue culture of claim 5 and capable of expressing all the morphological and physiological characteristics of
 3951. 